Aluminum oxide coated hafnium/nitrogen co-doped lithium iron phosphate positive electrode material and preparation method thereof

Abstract

Firstly, four raw materials, namely hafnium salt, a lithium source, a phosphorus source and an iron source, are mixed and subjected to heat treatment to obtain hafnium-doped lithium iron phosphate; secondly, the lithium iron phosphate precursor is re-placed into a mixed solution of aluminum nitrate, urea and glucose for secondary dispersion and mixing, and hydrothermal reaction is performed; and finally, the hydrothermal product is cleaned, dried and calcined to obtain the aluminum oxide coated hafnium / nitrogen co-doped lithium iron phosphate positive electrode material. The method has the advantages of simple process steps, short flow, adjustable morphology and structure and the like in the aspect of preparing the lithium iron phosphate positive electrode material. The prepared lithium iron phosphate positive electrode material has obvious advantages in the aspects of high-rate performance, cycle index, energy density and other electrochemical properties, the performance is more stable, the equipment requirement of the whole route is low, the process stability is good, and the material has important industrial popularization and application value.

Description

technical field [0001] The invention relates to the technical field of positive electrode materials for lithium ion batteries, and relates to an aluminum oxide-coated nitrogen / aluminum co-doped lithium iron phosphate positive electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, high power density, and long cycle life, and are widely used in electric vehicles, notebook computers, camcorders, and other electric equipment. In recent years, special equipment fields such as space flight devices and deep-sea diving equipment have also raised an urgent need for the use of lithium-ion batteries to provide durable power output. Lithium-ion cathode materials have a decisive impact on the energy density of lithium-ion batteries, which are generally lithium-containing variable-valence metal compounds. Currently widely used cathode materials for lithium-ion batteries mainly include lithium-r...

AI Technical Summary

Problems solved by technology

However, the problem at this stage is that the ion conductivity and electronic conductivity of lithium iron phosphate are relatively low, which is only suitable for charging and discharging at low current density. High-rate charging and discharging will reduce the specific capacity. Large-scale application in more fields

[0004] Although many modification methods have been developed at this stage, the prepared lithium iron phosphate materials cannot meet the needs of industrialization in terms of energy density, cycle performance, rate discharge and production costs.

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